The present invention is directed to an apparatus for manufacturing electrical assemblies, particularly for equipping printed circuit boards with electrical components, wherein the apparatus comprises a chassis with two linear longitudinal guides extending essentially parallel to one another for at least two carriages, for example beam-like carriages, which are movable on the guides and respectively provided with transverse bars that comprise transverse guides residing transversely for longitudinal guidance for at least one processing head for the assembly, which head is displaceable thereon.
U.S. Pat. No. 5,002,448, whose disclosure is incorporated herein by reference thereto, discloses an assembly device which has two beam-like carriages that are guided on two guide rails of a chassis, which rails are spaced apart and extend parallel to one another. Each of the carriages comprises a double-bearing at one end, which double-bearing engages one rail and serves for the exact longitudinal guidance and for adherence to the angular position of the carriage relative to the one guide rail. A simple bearing at the opposite end serves the purpose of supporting the transverse bar at this other guide rail.
The simple bearings herein, in fact, also exhibit guide properties that, however, lead to an over-definition of the bearing system and are basically not required. Here, the bearings are allocated to one another so that a double-bearing of the first carriage is respectively arranged at one side and a simple bearing of the other carriage is respectively arranged at the opposite side. Each double-bearing has a drive unit allocated to it, which will drive the carriage in the direction of the longitudinal guide. The two transverse bars are provided with transverse guides on which a triple-equipping head is respectively displaceable and is displaceable between a component delivery unit at the processing location of the chassis for the assembly in order to convey components obtained from the component delivery units up to their equipping location on the printed circuit board.
When it is assumed that the simple bearings, such as, for example, according to U.S. Pat. No. 4,836,111, whose disclosure is incorporated herein by reference thereto, should not have a guide function but only a supporting function, then it can be defined that each carriage is guided at one side along the longitudinal guide. The two carriages thus project from the longitudinal guides to the longitudinal guides lying there opposite, i.e., in opposite directions to one another.
An equipping location for an assembly is located between the two longitudinal guides. The two carriages are matched to one another in terms of their function so that they respectively place the components on the printed circuit boards or, respectively, obtain the components from the component delivery location in alternation.
European 0 315 799 and U.S. Pat. No. 4,875,285, whose disclosure is incorporated herein by reference thereto, for example, discloses an automatic equipping unit for printed circuit boards, wherein the equipping head is fashioned as a turret head for simultaneously picking up, for example, twelve components. It can thus occur that the two equipping heads simultaneously place components onto the printed circuit board and, thereby, mutually impede one another, particularly given large printed circuit boards.
The present invention is based on the object of enhancing the equipping capacity of an apparatus and reducing the manufacturing outlay for the apparatus, as well as facilitating accessibility to the apparatus.
This object is achieved in a means or apparatus for manufacturing electrical assemblies, particularly for equipping printed circuit boards with electrical components, which apparatus has a chassis with two linear longitudinal guides essentially parallel to one another for at least two carriages, for example beam-like carriages, which are displaceable on the guides, said carriages being provided with a transverse bar that comprises a transversely-residing transverse guide for a longitudinal guidance for at least one processing head for the printed circuit board being displaceable on the transverse guide, the carriages being guided in the longitudinal guides in an end region, and wherein the chassis comprises at least one processing location for at least one of the assemblies. The improvements are that the two longitudinal guides are arranged immediately adjacent to one another and the two transverse carriers respectively project from the longitudinal guides into a direction facing away from the neighboring longitudinal guide and at least two processing locations are provided on both sides of the longitudinal guide.
The processing heads can be differently fashioned so that they are suitable not only for equipping but also for hoop-soldering, measuring checking or testing printed circuit or, respectively, assembly. Other processing heads can be provided, for example, for applying fluxing agent, adhesive or solder paste.
As a result of the central arrangement of the guide rails and the transverse bars directed away from one another in, for example, the beam-like carriages, it is possible to simultaneously process two assemblies given comparable apparatus outlay without having the processing heads mutually impede one another. Another advantage is that only one shared control means is required for the two processing locations.
It is thereby possible to significantly enhance the processing capacity of the machine. As a result of the central arrangement of the longitudinal guides, the accessibility to the machine from the outside is substantially improved, with it being possible to also arrange the component deliveries at the outside of the machine to extend parallel to the longitudinal guides. As a result of the centralization of the longitudinal guides, in addition, the leads to the drives can also be combined in the middle. The carriers for the two longitudinal guides can be structurally connected to one another so that they mutually reinforce one another.
A table and compact structure of the supporting structure will occur due to the shared longitudinal carrier, wherein the two longitudinal guides are fashioned as a common longitudinal carrier of the chassis, so that the chassis can be cost-beneficially constructed. A beneficial center of mass also occurs in the middle, as a result whereof the vibration behavior is also improved and the stability of the chassis is enhanced.
As a result of the drive units, which are allocated to the longitudinal guides for displacing the carriages, the drive units and the guide means for the carriages can be compactly combined, which will enable a weight-saving and stable embodiment.
Preferably, an assembly transport comprising a conveyor direction oriented perpendicular to the longitudinal guides will service both processing locations. Thus, the printed circuit boards can be conducted to both processing locations in one conveyor line.
If the apparatus has the chassis having at least one linear longitudinal guide for at least one carriage, for example a beam-like carriage displaceable on the guide, and the improvement includes that two carriages are movable independent of one another are guided on this guide, it is possible to further enhance the processing capacity of the machine. For example, it is thereby also possible to allocate a different plurality of carriages to the two longitudinal guides. In addition, the processing heads can exercise different functions. A respectively optimum configuration of processing heads can be formed in this way for different processing jobs.
If the supporting and guide elements are arranged at the end of the carriage, and if the longitudinal guide is provided with at least one supporting path and at least one guideway for the corresponding supporting guide elements, it makes it possible to fashion a transverse bar freely projecting at its free end so that no guide or support means is required. The accessibility to the work area of the machine is thus further improved. It then is also possible to arrange peripheral devices as additional component magazines or other auxiliary devices along the outside of the apparatus adjacent to the free ends of the carriages.
The supporting and guideways lying perpendicularly above one another require less structure width than given a horizontal arrangement. The overall width of the machine can thus be correspondingly reduced. Moreover, all supporting and guideways of both longitudinal guides can be beneficially combined into one carrier part having a compact structure.
Preferably, the drive unit for each carriage is fashioned as a linear motor and is allocated to the linear guide. Since the linear motor requires no additional drive means, such as spindles or toothed belts, the use of a plurality of carriages at the longitudinal guide is facilitated by the use of the linear motors. Such a linear motor is composed of a stationary part, for example a magnetic rail, that extends over the entire length of the longitudinal guide. An electromagnetically active part is allocated to the carriage, and this is located in close interactive connection with the magnetic rail and is controllable, so that the carriage can be moved into the exact predetermined position. Preferably, the linear motor is arranged between the supporting path and the guideway. This arrangement allows the guide and drive means for the carriage to be combined to form a compact and space-saving arrangement.
Preferably, a parting gap lies between the mobile part and the stationary part of the linear motor in the region of the supporting path and guideway, and this parting gap and mutual contacting surfaces between the guide elements of the longitudinal guide form a through common parting seam, so that the guide element of the longitudinal guide and the parts of the linear motor cooperate in an especially advantageous way. The magnetic forces of the linear motor are utilized for drawing the supporting and guide elements of the carriage against the support and guideways of the longitudinal guide play-free and in a defined fashion, so that the transverse guide of the carriage is held in an exact angular and height position, and the guide means engaging therebehind can be foregone. The longitudinal guide thus requires, for example, only one real-like guideway and the supporting path proceeding parallel thereto for exact longitudinal guidance and for adherence to the angular position of the transverse bar relative to the chassis. The permanent attractive forces of the magnetic rail are so high that the carriage is reliably held at the longitudinal guide, even after the linear motor is shut off.
Preferably, the stationary bar is provided as a common stationary element for a plurality of independently-actuatable linear motors of the carriages, and the stationary part is rigidly connected to the longitudinal carrier of the chassis. Thus, only a single stationary part is required for the mobile parts of the linear motor. This single stationary part is constructed, for example, as a simple magnetic rail and is embedded in the longitudinal carrier in a space-saving fashion.
Other advantages and features of the invention will be readily apparent from the following description of the exemplary embodiment, the drawings and claims.